Project Summary/Abstract The Within?Family Differences Study?Bereavement (WFDS?B) considers how intergenerational relationships across time affect the psychological well?being, physical health, and health behaviors of 787 adult children and 1182 adult grandchildren nested in 337 three?generation families following the deaths of members of the oldest generation. The WFDS?B builds upon the groundbreaking findings of the Within?Family Differences Study (WFDS), a 2?wave investigation that documented the strong effects of within?family differentiation in older parents? relationships with their offspring on the psychological and relational well?being of adult children. The WFDS?B will extend the original 2?generation WFDS panel to include adult grandchildren. The WFDS?B will use data collected from multiple adult children and adult grandchildren in the same families to identify how prior within?family differences in parent?child and grandparent?grandchild relations, particularly parental differential treatment, impact the psychological well?being (e.g., depressive symptoms, uplifts, resilience), physical health (e.g., subjective health, physical limitations), and health behaviors (e.g., smoking, drinking, sleeping, exercising) of the middle and youngest generations following the deaths of members of the oldest generation. Data on adult children?s (G2) relationships with their parents (G1) were collected from both generations at T1 and T2 of the WFDS; data on adult grandchildren?s (G3) relationships with G2s and G1s will be collected both currently and retrospectively in the WFDS?B. Approximately 25% of the WFDS?B panel is Black, allowing us to highlight race differences in the ways in which relationships within and between generations moderate health and well?being following the loss of family members, contributing to the study of racial health disparities. We anticipate that 50% of the grandmothers and more than 60% of the grandfathers living at T2 will have died by 2019. Thus, we will be able to compare the well?being of G2s and G3s whose parents/grandparents did and did not die since T2, as well as investigate how variations in the history of family relationships moderate the grief and well?being of those whose parents/grandparents died. Finally, the lag between the WFDS?II (2008?11) and WFDS?B (2019?21) permits examining heterogeneity in changes in well?being after parents/grandparents? deaths as a function of time elapsed since the loss. Past success of the WFDS?I & II and 2017 WFDS?B Feasibility Pilot demonstrated our ability to maintain high participation of G2s and secure contact information for adult G3s.